Spark plug



July 7, 1925.

c. L. BRADEN Filed N 7, 19

m ,4 5 a M 2 Patented July 7, 1925.

UNITED STATES i A 1,544,630 PATENT OFFICE.

CLEMENT L. BRADEN, OF ANDERSON,'INDIANA.'

SEAR]! PLUG.

Application filed November 7, 1923. Serial No. 678,8?1.

To all whom it may concern:

Be it known that I, CLEMENT L. BRADEN, a citizen of the United States,residing at Anderson, in the county of Madison and State of Indiana,have invented or discovered certain new and useful Improvements in SparkPlugs, of which the following is a specification, reference being hadtherein to the accompanying drawing.

This invention has for its object to provide a spark plug, for internalcombustion engines, which will be of such construction that the lowerpart of the casing or shell of the spark plug, and which extends intothe combustion chamber of the engine, will serve as a guard to preventoil from coming in contact with the central electrode of the plug, asalso to provide an eflicient spark gap construction and a heatingchamber adjacent thereto, as will hereinafter more fully appear. I

The accompanying drawing is a vertical section of the improved sparkplug.

Referring to the drawing, 12 denotes the spark plug shell or casinghaving an externally screw-threaded portion 13 to be screwed into theengine cylinder. The up per part of the casing or shell 12 isscrewthreaded internally for the reception of a nut 14 by which theinsulation member 15 is secured in place in the usual manner. The

positive electrode is in the form of a pin 16 provided at its top with ascrew-threaded part on which the nuts 17 and 18 are mounted and by whichthe said electrode. is secured in place. The parts thus far describedare or may be of any preferred or usual construction, and the novelfeatures of the improved spark plug will now be described.

The lower part of the shell or casing 12 is' formed with an annulardownwardly tapering thin part 19 preferably formed concave, as shown,and below the said tapering part is formed an outwardlyv extendingflange 20, which is preferably curved, as shown. Within the wall 19 is aheating chamber 21. As is well known many spark plugs are fixed in theengine cylinders in inclined positions, and the construction justdescribed serves as a guard to prevent oil from, dripping onto thepositive electrode 16, such guard being more efficient, for the purposeust referred to, when the spark plug is in an inclined position.

The inner lower end of the wall 19 is constructed as a thin inwardlyextending flange 22 which serves as the negative electrode of the plug,the spark gap 23 being located between said flange 22 and the positiveelectrode 16. It will be noted that the wall of the chamber 21 is formedthin so that it will readily become heated and will thus serve to heatthe chamber 21 so as to heat and dry out the gas mixture which may entersaid chamber.

The bottom part of the casing, having the inwardly extending negativeelectrode flange 22 and the outwardly extending oil guard flange 20, isformed flat, as shown, so that oil will not readily, creep inward.

The positive electrode 16 is of a proper length to extend below thespark gap 23, so that any oil which might by any possibility come incontact with the said electrode will be below the spark gap and willthus naturally drip off the said electrode into the chamber of theengine cylinder. Thus this downwardly extending lower end of thepositive electrode will serve as a guard for the negative electrodeafl'orded by the flange 22.

From the foregoing it will be apparent that the novel construction abovedescribed of the lower end of the spark plug will serve as effectiveguards to prevent oil and carbon from lodging on the electrodes of.

the plug at the sparking or firing point, while the chamber above thespark gap will readily become heated to facilitate combustion of thegas, and only a dry mixture of gas can enter said chamber.

Having thus described my invention I claim and desire to secure byLetters Patent:

A spark plug comprising a shell or casing formed with a downwardlytapering lower ,part having a thin wall and a flat bottom,

said thin wall terminating in a thin, inwardly extending flange, servingas a negative electrode, and an outwardly extending flange serving as anoil guard, combined with a ositive electrode insulatingly sup ported insaid casing and extending below said negative electrode flange, with aspark gap between said electrodes.

In testimony whereof I affix my signature.

CLEMENT L. 'BRADEN.

